Swiss pharmaceuticals chief, Bertarelli, 45, is a twice winner of the prestigious America's Cup yacht race and is worth a reputed £6.8billion, making him the 81st richest man in the world and the fifth richest in the UK.

His wife is currently ranked the UK's richest woman.

Vava II took more than 200 craftsmen over two years to build at the Devonport Dockyard in Plymouth after the hull was built in Appledore in Devon.

Britain's richest woman: Kirsty Bertarelli has had Britain's largest yacht built in Plymouth

Stunning: Kirsty Bertarelli when she won Miss UK in 1988 when she was 17, she now lives in Switzerland

The incredible high tech specification for Britain's largest ever built yacht also includes a fold-down beach club and a pool which can be varied in depth to cater for guest preferences.

Known during the build process as Project-55 the exterior finishes on the superyacht have been designed by Hampshire-based specialists Redman Whiteley Dixon while the interiors have been styled by Remi Tessier.

All the engineering on the state of the art ship was carried out by workers at the Devonport Royal Dockyard. The luxury yacht builders, Devonport Yachts, was bought from dockyard owners Babcock last year by Falmouth-based Pendennis shipyard.

Yachtmaster: Ernesto Bertarelli, centre, on his America's Cup winning yacht Alinghi. He and his wife have just bought a £100m superyacht after a two year build.

Successful: Kirsty Bertarelli embraces her husband after he and his crew won the coveted America's Cup

Sea trials will start next week to
test the design of the multi-million pound boat which can be seen in
dock and is visible in Plymouth Sound.

Detailed specifications for the incredible boat have remained a closely guarded secret throughout the two-year build.

Managing Director Stephen Hills said the vessel was 'anabsolute credit to the capacity of the South West as a superyacht building location'.

He added: 'We are looking to continue this industry in the South West.'

And the man who will helm Britain's largest home-built yacht Brendan O'Shannassy, said of the yacht: 'To have such a ground breaking construction unveiled in Plymouth should make the region justly proud.'

It is possible that the huge superyacht will be chartered for part of the year to wealthy clients while it is not being used by it's super rich owners.

Hiring a yacht of the calibre of Vava II can cost ten of thousands of pounds a week and if chartered the Bertarelli's yacht will set a new standard in the rental market next year.

Mr Bertarelli won the America's Cup yacht race in 2003 and 2007 when he crewed his Team Alinghi boat.